WASHINGTON (AP) - Snow blew across the Midwest on Tuesday and headed for the hard-hit Mid-Atlantic region, where federal government offices have been closed since last week and utility workers struggled to restore power already knocked out by a weekend blizzard.

The latest storm hit the Midwest early, closing schools and greeting commuters with slick, slushy roads from Minneapolis and Chicago to Louisville, Ky. Hundreds of flights were canceled at Chicago's airports as the storm moved across Illinois, where up to a foot of snow was forecast.

Powerful winds and snow were expected to hit Mid-Atlantic states by the afternoon, and could leave as much as 20 inches of new snow in Washington and 18 inches near Philadelphia - a Northeast travel hub - by Wednesday night. New York City announced students would have a rare snow day Wednesday, only the third in six years.

Parts of the region were already buried under nearly 3 feet.

In rural Maryland, a state police helicopter rescued a man stranded in a remote mountaintop home where he had been staying alone with no electricity since the storm this past weekend.

On Capitol Hill, the House called off all votes for the week because many members couldn't get back from their districts. A committee hearing on the Toyota gas pedal recall was postponed. The Senate was scheduled to hold two votes later Tuesday, as Senate Majority Leader Harry Reid tried to bring senators back to Washington to take up a jobs package.

The White House, meanwhile, moved a Black History Month concert featuring Bob Dylan, Smokey Robinson and Natalie Cole up a day to try to beat the storm. President Barack Obama held a bipartisan meeting with congressional leaders and joked that it went so well that Reid and Republican Sen. Mitch McConnell of Kentucky had gone out to play in the snow.

"In fact, I understand that McConnell and Reid are out doing snow angels on the South Lawn together," Obama joked as he made an unannounced stop in the White House briefing room.

Residents worried they might be stuck at home hit grocery stores to stock up. A Safeway grocery store in the Dupont Circle area of Washington had milk and some bread Tuesday, but many other items were picked over from the last storm. There was no shredded cheese, and people who wanted Diet Coke or Brussels sprouts were out of luck.

David Fiore, 49, a federal employee off for the second day, left with two bags of groceries. He had gone to four stores looking for milk the night before, but they were either out of it or too crowded. By Tuesday morning, Safeway had restocked, so he left with a gallon of milk, more than he usually buys.

"It's that sort of hoarding instinct," he said.

Airlines that shut down flights to Washington over the weekend warned that more would be canceled and that travelers who didn't depart by Tuesday night were likely out of luck. In Chicago, Southwest Airlines canceled all of its flights at Midway International Airport through Wednesday morning.

James Allen, 25, of Northampton, England, arrived Sunday on the first flight to land at Baltimore's airport after its runway reopened from the last storm. He was visiting friend Julia Tracey, 25, a nurse at Johns Hopkins Hospital, and the two were at a SuperFresh downtown Tuesday searching in vain for fresh herbs for a recipe.

Allen said the United Kingdom has also endured a colder-than-usual winter, but it can't compare to what the Mid-Atlantic is going through. He had planned to stay in Baltimore for a few days, but "it's probably going to turn into a few weeks now."

The storm brought out the best in some: In Alexandria, Va., when word got out that a family living at the bottom of a hill on an unplowed street needed to get their teenage daughter whose cancer is in remission out to an important doctor's appointment, neighbors quickly converged. The entire street was shoveled before many neighbors even had shoveled their own driveways. Up the street, children tired of playing outside in the snow created craft items and had an impromptu sale to benefit victims of the earthquake in Haiti.

In West Virginia, where 40 counties were under winter storm warnings, Gov. Joe Manchin urged people to make sure snow was cleared from roofs of public buildings to avoid a repeat of 1998, when cave-ins were blamed for at least three deaths. Collapses have already been reported at a mobile home in Delaware and a food warehouse in North Dakota.

Some spots, including parts of Maryland, had nearly 3 feet of snow from the earlier storm. One scientist said if all that fell on the East Coast were melted, it would fill 12 million Olympic swimming pools or 30,000 Empire State buildings. Philadelphia and Washington each need about 9 more inches to give the cities their snowiest winters since 1884, the first year records were kept.

The storm that began Friday closed schools, and some 230,000 federal workers in Washington had Monday and Tuesday off. Power was still out for tens of thousands of homes and businesses, and utilities said deep snow was hindering some crews trying to fix damaged power lines before the next storm hits.

A new wave of cold residents checked into the Hilton in Silver Spring, Md., including Bill and Ann Hilliard and their two elderly cats. Temperatures in their powerless home had dropped into the 40s and with another foot of snow forecast, they didn't want to stay home.

Ann Hilliard recently had part of her leg amputated and their neighbors helped them out of the neighborhood.

"There was no way to get her out otherwise," he said.

Associated Press writers Jessica Gresko, Laurie Kellman, Philip Elliott and Nafeesa Syeed in Washington; Sarah Karush in Falls Church, Va.; Brian Witte in Annapolis, Md.; Marc Levy in Harrisburg, Pa.; Nancy Benac in Arlington, Va.; Tom Breen in Charleston, W.Va.; Joann Loviglio in Philadelphia and Sarah Brumfield and Stephanie Stoughton in Silver Spring, Md., contributed to this story.